Electrochemical cell and electrochemical cell stack

Abstract

To suppress a decrease in the amount of electrochemical reaction.SOLUTION: An electrochemical cell according to an embodiment includes an electrode plate, a flow path plate, an electrode plate outer frame, and a flow path plate outer frame. The electrode plate outer frame and the flow path plate outer frame have an anode fluid communication hole and a cathode fluid communication hole communicating in a stacking direction. The electrochemical cell further includes: an anode communication groove for communicating the anode fluid communication hole and an anode flow path; and a cathode communication groove for communicating the cathode fluid communication hole and a cathode flow path. The electrode plate outer frame is configured by laminating a plurality of sheet materials in the stacking direction with an adhesive. The electrode plate outer frame has a void part with which no sheet material and adhesive are provided, at a position overlapping at least one of the anode communication groove and the cathode communication groove in plan view. A reinforcing sheet is provided in the void part of the electrode plate outer frame.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to electrochemical cells and electrochemical cell stacks. [Background technology]

[0002] Electrochemical cells consist of an anode electrode and a cathode electrode, which are arranged across a membrane such as an electrolyte membrane. A fluid (hereinafter referred to as an anode fluid, a cathode fluid, or the like) consisting of a liquid, a gas, or a mixture of a liquid and a gas is supplied to at least one of the electrodes. An external potential difference is applied between the anode electrode and the cathode electrode, causing a current to flow. This causes ionized substances to pass through the membrane, resulting in an electrochemical reaction. Electrochemical cells are used, for example, for water electrolysis, in which water (HO) is supplied to the anode side and hydrogen (H) is extracted from the cathode outlet side, or for carbon dioxide electrolysis, in which water (HO) is supplied to the anode side and carbon dioxide (CO) is supplied to the cathode side and carbon monoxide (CO) is extracted from the cathode outlet side. To promote the electrochemical reaction, an electrolyte solution, in which a small amount of ionic substance is dissolved in the liquid required for the reaction, may also be used as the anode fluid or cathode fluid.

[0003] To supply the anode and cathode electrodes with anode fluid and cathode fluid, respectively, flow path plates are installed adjacent to the anode and cathode electrodes. The flow path plates have flow paths for the anode and cathode fluids to flow through. Furthermore, the flow path plates are made of a conductive material so that the electrodes are connected in series when multiple electrode plates and flow path plates are stacked.

[0004] Even if pure water is used as the anode or cathode fluid, it is difficult to achieve zero conductivity due to the influence of impurities mixed in the fluid. Current flows between different flow path plates through the connecting holes of the stacked flow path plates, and some of the current that should be used for the electrochemical reaction is consumed as leakage current. Furthermore, if an electrolyte solution is used as the fluid, the conductivity increases further, and the leakage current also increases. Even if the anode or cathode fluid is mainly a gaseous fluid, some of the contained substances condense and adhere to the wall surfaces of the connecting holes, which can similarly cause leakage current.

[0005] Therefore, a method has been proposed in which an electrode plate outer frame is disposed outside the electrode plate, and a flow path plate outer frame is disposed outside the flow path plate. The electrode plate outer frame and the flow path plate outer frame are provided with communication holes for supplying anode fluid and cathode fluid from outside the electrochemical cell. The anode fluid and cathode fluid from the communication holes pass through communication grooves disposed on both sides of the flow path plate outer frame and then flow into the flow paths disposed on both sides of the flow path plate. Here, the contact portions between the electrode plate outer frame and the flow path plate outer frame and the anode fluid and the cathode fluid, respectively, are made of an electrically insulating material. This configuration insulates the portions of the flow paths between the communication holes and the flow path plate that come into contact with the fluids. This reduces leakage current flowing between adjacent flow path plates across the electrode plate.

[0006] Another proposed method involves stacking multiple sheet materials in the stacking direction to form the electrode plate outer frame and / or the flow path plate outer frame. The multiple sheet materials are bonded together, for example, with an adhesive. This configuration allows the electrode plate outer frame and the flow path plate outer frame to be produced relatively inexpensively, thereby reducing the manufacturing cost of the electrochemical cell. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-121001 [Patent Document 2] Japanese Patent Application Publication No. 2023-85988 Summary of the Invention [Problem to be solved by the invention]

[0008] In order to increase the electrochemical reaction rate, such electrochemical cells are generally stacked in multiple layers to form a cell stack structure. In this case, a certain pressure is applied to the electrochemical cells in the stacking direction by fastening or the like to tightly bond the electrode plates and flow path plates.

[0009] However, as described above, when multiple sheet materials of the electrode plate outer frame and / or flow path plate outer frame are bonded in the stacking direction with an adhesive, the adhesive bonding the sheets together may be deformed by pressure, which may cause the communication grooves arranged in the flow path plate outer frame to collapse. If the communication grooves collapse, the flow path area for the anode fluid and cathode fluid to flow may decrease, which may reduce the amount of electrochemical reaction.

[0010] In view of the above, the present embodiment aims to provide an electrochemical cell and an electrochemical cell stack that can suppress a decrease in the amount of electrochemical reaction. [Means for solving the problem]

[0011] An electrochemical cell according to an embodiment includes an electrode plate having a diaphragm, an anode electrode disposed on one main surface of the diaphragm, and a cathode electrode disposed on the other main surface of the diaphragm; a flow path plate stacked on the electrode plate in the stacking direction, the flow path plate being disposed opposite the anode electrode and having an anode flow path through which an anode fluid flows, and a cathode flow path being disposed opposite the cathode electrode and through which a cathode fluid flows; an electrode plate outer frame joined to the outer periphery of the electrode plate; and a flow path plate outer frame joined to the outer periphery of the flow path plate. The electrode plate outer frame and the flow path plate outer frame have anode fluid communication holes and cathode fluid communication holes that communicate in the stacking direction. The electrochemical cell further includes an anode communication groove that communicates the anode fluid communication hole with the anode flow path, and a cathode communication groove that communicates the cathode fluid communication hole with the cathode flow path. The electrode plate outer frame is formed by bonding multiple sheet materials together in the stacking direction with an adhesive. The electrode plate outer frame has a gap portion where no sheet material or adhesive material is provided at a position that overlaps with at least one of the anode connection groove and the cathode connection groove in a planar view, and a reinforcing sheet is provided in the gap portion of the electrode plate outer frame.

[0012] An electrochemical cell according to an embodiment includes an electrode plate having a diaphragm, an anode electrode disposed on one main surface of the diaphragm, and a cathode electrode disposed on the other main surface of the diaphragm; a flow path plate stacked on the electrode plate in the stacking direction, the flow path plate being disposed opposite the anode electrode and having an anode flow path through which an anode fluid flows, and a cathode flow path being disposed opposite the cathode electrode and through which a cathode fluid flows; an electrode plate outer frame joined to the outer periphery of the electrode plate; and a flow path plate outer frame joined to the outer periphery of the flow path plate. The electrode plate outer frame and the flow path plate outer frame have anode fluid communication holes and cathode fluid communication holes that communicate in the stacking direction. The electrochemical cell further includes an anode communication groove that communicates the anode fluid communication hole with the anode flow path, and a cathode communication groove that communicates the cathode fluid communication hole with the cathode flow path. The flow path plate outer frame is formed by bonding multiple sheet materials together in the stacking direction with an adhesive. The flow path plate outer frame has a void portion where no sheet material or adhesive material is provided at a position that overlaps with at least one of the anode connection groove and the cathode connection groove in a planar view, and a reinforcing sheet is provided in the void portion of the flow path plate outer frame.

[0013] An electrochemical cell stack according to an embodiment includes a plurality of the above-described electrochemical cells stacked on top of each other. [Effects of the Invention]

[0014] According to this embodiment, it is possible to suppress a decrease in the amount of electrochemical reaction. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of an electrochemical cell stack according to one embodiment. [Figure 2] FIG. 2 is a perspective view of an electrochemical cell according to one embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. [Figure 4] FIG. 4 is a plan view of the electrode plate and the electrode plate outer frame of FIG. [Figure 5]FIG. 5 is a view of the electrode plate and the electrode plate outer frame of FIG. 4 as seen from the back side. [Figure 6] FIG. 6 is a plan view of the flow path plate and the flow path plate outer frame of FIG. [Figure 7] FIG. 7 is a view of the flow path plate and the flow path plate outer frame of FIG. 6 as seen from the back side. [Figure 8] FIG. 8 is a cross-sectional view taken along line BB in FIG. [Figure 9] FIG. 9 is an enlarged cross-sectional view of a portion of a typical electrochemical cell stack. [Figure 10] FIG. 10 is a cross-sectional view showing a state in which the communication groove of FIG. 9 is crushed. [Figure 11] FIG. 11 is a plan view of a flow path plate and a flow path plate outer frame according to one modified example. [Figure 12] FIG. 12 is a view of the electrode plate and the electrode plate outer frame of FIG. 11 as seen from the back side. DETAILED DESCRIPTION OF THE INVENTION

[0016] An electrochemical cell and an electrochemical cell stack according to an embodiment of the present invention will now be described with reference to the drawings.

[0017] Fig. 1 is a perspective view of an electrochemical cell stack 1 according to one embodiment. As shown in Fig. 1, the electrochemical cell stack 1 includes a plurality of electrochemical cells 2 stacked on one another. The electrochemical cell stack 1 is configured by stacking a plurality of electrochemical cells 2.

[0018] As shown in FIG. 1 , the electrochemical cell stack 1 includes an insulating plate 3, a current collecting plate 4, and a clamping plate 5. The insulating plate 3 is a plate-shaped insulator. The insulating plate 3 is disposed on both sides of the stacked electrochemical cells 2 in the stacking direction. The current collecting plate 4 is a plate-shaped conductor. The current collecting plate 4 may be embedded in each insulating plate 3. The current collecting plate 4 has a terminal 4 a extending outward. The terminal 4 a is electrically connected to an external power supply via a cable or the like. This allows a voltage to be applied from the external power supply to each electrochemical cell 2, causing a current to flow. The clamping plate 5 is disposed on both sides of each electrochemical cell 2 and insulating plate 3 in the stacking direction. The clamping plate 5 clamps the electrochemical cells 2 in a direction approaching each other. The clamping plate 5 may be fixed by a tie rod 6. The clamping plate 5 may clamp the electrochemical cells 2 in a direction approaching each other by the clamping force of the tie rod 6.

[0019] 1 , the clamping plate 5 has an anode fluid inlet hole 7a, an anode fluid outlet hole 7b, a cathode fluid inlet hole 7c, and a cathode fluid outlet hole 7d. These inlet holes 7a, 7c and outlet holes 7b, 7d penetrate the clamping plate 5. The anode fluid inlet hole 7a communicates with anode fluid inlet manifolds 12 and 22 of the electrochemical cell 2, which will be described later. The anode fluid outlet hole 7b communicates with anode fluid outlet manifolds 13 and 23 of the electrochemical cell 2, which will be described later. The cathode fluid inlet hole 7c communicates with cathode fluid inlet manifolds 14 and 24 of the electrochemical cell 2, which will be described later. The cathode fluid outlet hole 7d communicates with cathode fluid outlet manifolds 15 and 25 of the electrochemical cell 2, which will be described later. An anode fluid supplied from the outside flows into the anode fluid inlet hole 7a. After the electrochemical reaction in each electrochemical cell 2, the anode fluid flows out from anode fluid outlet hole 7b to the outside. Cathode fluid supplied from the outside flows into cathode fluid inlet hole 7c. After the electrochemical reaction in each electrochemical cell 2, the cathode fluid flows out from cathode fluid outlet hole 7d to the outside.

[0020] Fig. 2 is a perspective view of an electrochemical cell 2 according to one embodiment. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. As shown in Figs. 2 and 3, the electrochemical cell 2 includes an electrode plate 10 and an electrode plate outer frame 11, and a flow path plate 20 and a flow path plate outer frame 21. The electrochemical cell 2 has a structure in which the electrode plate 10 and the electrode plate outer frame 11, and the flow path plate 20 and the flow path plate outer frame 21 are stacked as a set.

[0021] Fig. 4 is a plan view of the electrode plate 10 and the electrode plate outer frame 11 of Fig. 3. Fig. 5 is a view of the electrode plate 10 and the electrode plate outer frame 11 of Fig. 4 as viewed from the back. As shown in Figs. 3 to 5, the electrode plate 10 has a diaphragm 16, an anode electrode 17, and a cathode electrode 18. The anode electrode 17 and the cathode electrode 18 are arranged with the diaphragm 16 sandwiched between them. That is, the anode electrode 17 and the cathode electrode 18 are arranged on either side of the diaphragm 16. The anode electrode 17 is arranged on one main surface of the diaphragm 16 (upper side in Fig. 3), and the cathode electrode 18 is arranged on the other main surface of the diaphragm 16 (lower side in Fig. 3).

[0022] The diaphragm 16 may be an ion filtration membrane such as a solid polymer membrane (ion exchange membrane) or a solid electrolyte membrane (electrolyte membrane). The anode electrode 17 and the cathode electrode 18 may be configured by attaching a catalyst containing a metal such as nickel, iridium, gold, silver, or platinum, or a metal oxide such as nickel oxide, iridium dioxide, or cobalt oxide to a gas-permeable substrate made of carbon or metal.

[0023] 3 to 5, an electrode plate outer frame 11 is disposed on the outside of the electrode plate 10. The electrode plate outer frame 11 is joined to the outer periphery of the electrode plate 10.

[0024] As shown in Fig. 3, the electrode plate outer frame 11 may be formed by bonding a plurality of sheet materials together in the stacking direction with an adhesive. In the example shown in Fig. 3, the electrode plate outer frame 11 is formed by bonding three sheet materials 11a, 11b, and 11c together in the stacking direction with an adhesive 11f. In the electrode plate outer frame 11 shown in Fig. 3, the sheet material 11a, the sheet material 11b, and the sheet material 11c are arranged in this order from one side in the stacking direction (the upper side in Fig. 3). The sheet materials 11a and 11b are bonded to each other with an adhesive 11f, and the sheet materials 11b and 11c are also bonded to each other with an adhesive 11f.

[0025] 3, the outer periphery of the electrode plate 10 may be sandwiched between two sheet materials 11a and 11c, and the outer periphery of the electrode plate 10 may be bonded to the sheet materials 11a and 11c with adhesive 11f.

[0026] The sheet materials 11a, 11b, and 11c may be made of an electrically insulating material, such as a resin material such as fluororesin, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), or polyethylene naphthalate (PEN), or a rubber material such as fluororubber, ethylene propylene diene rubber (EPDM), or silicone rubber. The sheet materials 11a, 11b, and 11c may also be made of a highly rigid material such as a metal plate. For example, the sheet material 11b (inner sheet material) that does not contact fluids such as the anode fluid or the cathode fluid may be made of a highly rigid material such as a metal plate, and the sheet materials 11a and 11c (outermost sheet material) that contact the fluids may be made of an electrically insulating material. The sheet materials 11a and 11c that contact the fluids may also be made of a conductive substrate such as a metal plate coated with an electrically insulating material. The sheet materials 11a and 11c that contact the fluids only need to have an electrically insulating material at least in the portions that contact the fluids.

[0027] The adhesive 11f may have electrical insulation properties and heat resistance. The adhesive 11f may have heat resistance of, for example, 100 degrees or more so that it can withstand the heat during the electrochemical reaction. The adhesive 11f may be, for example, an acrylic adhesive, a silicon adhesive, or an epoxy adhesive.

[0028] 4 and 5, the electrode plate outer frame 11 has an anode fluid inlet manifold 12, an anode fluid outlet manifold 13, a cathode fluid inlet manifold 14, and a cathode fluid outlet manifold 15. The anode fluid inlet manifold 12 and the anode fluid outlet manifold 13 are also simply referred to as anode fluid manifolds. The cathode fluid inlet manifold 14 and the cathode fluid outlet manifold 15 are also simply referred to as cathode fluid manifolds. These manifolds 12, 13, 14, and 15 are each located away from the electrode plate 10. These manifolds 12, 13, 14, and 15 each penetrate the electrode plate outer frame 11 in the thickness direction (stacking direction).

[0029] FIG. 6 is a plan view of the flow path plate 20 and flow path plate outer frame 21 of FIG. 3. FIG. 7 is a view of the flow path plate 20 and flow path plate outer frame 21 of FIG. 6 as viewed from the back side. As shown in FIGS. 3, 6, and 7, the flow path plate 20 has an anode flow path 26 and a cathode flow path 27. The anode flow path 26 and the cathode flow path 27 are arranged on both sides of the flow path plate 20. The anode flow path 26 is arranged on the surface of the flow path plate 20 facing the anode electrode 17 (the lower side in FIG. 3), and the cathode flow path 27 is arranged on the surface of the flow path plate 20 facing the cathode electrode 18 (the upper side in FIG. 3). The anode flow path 26 is arranged opposite the anode electrode 17 of the electrode plate 10, and the cathode flow path 27 is arranged opposite the cathode electrode 18 of the electrode plate 10.

[0030] The anode flow channel 26 is configured to allow the anode fluid to flow through it. As shown in Fig. 3, the anode flow channel 26 may be configured by recesses and projections formed on the surface of the flow channel plate 20 facing the anode electrode 17, and the anode fluid may flow through these recesses and projections. As shown in Fig. 7, the anode flow channel 26 may be a serpentine flow channel having multiple bends.

[0031] The cathode flow channel 27 is configured to allow the cathode fluid to flow through it. As shown in Fig. 3, the cathode flow channel 27 may be configured by recesses and projections formed on the surface of the flow channel plate 20 facing the cathode electrode 18, and the cathode fluid may flow through these recesses and projections. As shown in Fig. 6, the cathode flow channel 27 may be a serpentine flow channel having multiple bends.

[0032] The anode flow channel 26 and the cathode flow channel 27 may be formed by pressing a thin plate that will become the flow channel plate 20. That is, by pressing, concaves and convexes may be formed on the surface of the flow channel plate 20 that faces the anode electrode 17, and concaves and convexes may be formed on the surface of the flow channel plate 20 that faces the cathode electrode 18. The concaves and convexes formed on the surface of the flow channel plate 20 that faces the anode electrode 17 may be the anode flow channel 26, and the concaves and convexes formed on the surface of the flow channel plate 20 that faces the cathode electrode 18 may be the cathode flow channel 27. In this case, the concaves of the concaves and convexes of the concaves and convexes of the anode flow channel 26 correspond to the convex parts of the concaves and convexes ... of the cathode flow channel 27.

[0033] The flow path plate 20 may be made of a conductive material such as carbon, a mixture of carbon and resin, or metal. The flow path plate 20 may also be made of a conductive material whose surface is coated with a conductive coating agent for the purposes of increasing the corrosion potential, reducing contact resistance, etc.

[0034] 3, 6, and 7, a flow path plate outer frame 21 is disposed on the outer side of the flow path plate 20. The flow path plate outer frame 21 is joined to the outer periphery of the flow path plate 20.

[0035] As shown in FIG. 3, the flow path plate outer frame 21 may be configured by bonding multiple sheet materials together in the stacking direction with an adhesive. In the example shown in FIG. 3, the flow path plate outer frame 21 is configured by bonding five sheet materials 21a, 21b, 21c, 21d, and 21e together in the stacking direction with an adhesive 21f. In the flow path plate outer frame 21 shown in FIG. 3, the sheet materials 21a, 21b, 21c, 21d, and 21e are arranged in this order from one side in the stacking direction (the upper side in FIG. 3). The sheet materials 21a and 21b are bonded to each other with an adhesive 21f, and the sheet materials 21b and 21c are also bonded to each other with an adhesive 21f. The sheet materials 21c and 21d are bonded to each other with an adhesive 21f, and the sheet materials 21d and 21e are also bonded to each other with an adhesive 21f.

[0036] 3, the outer periphery of the flow path plate 20 may be sandwiched between two sheet materials 21b and 21d. The outer periphery of the flow path plate 20 may be bonded to the sheet materials 21b and 21d with adhesive 21f.

[0037] The sheet materials 21a, 21b, 21c, 21d, and 21e may be made of an electrically insulating material, such as a resin material such as fluororesin, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), or polyethylene naphthalate (PEN), or a rubber material such as fluororubber, ethylene propylene diene rubber (EPDM), or silicone rubber. The sheet materials 21a, 21b, 21c, 21d, and 21e may also be made of a highly rigid material such as a metal plate. For example, the sheet materials 21b, 21c, and 21d (inner sheet materials) that do not come into contact with fluids such as the anode fluid or the cathode fluid may be made of a highly rigid material such as a metal plate, while the sheet materials 21a and 21e (outermost sheet materials) that come into contact with the fluids may be made of an electrically insulating material. The sheet materials 21a and 21e that come into contact with the fluids may also be made of a conductive substrate such as a metal plate coated with an electrically insulating material. The sheet materials 21a and 21e that come into contact with the fluid only need to be provided with an electrically insulating material at least in the portions that come into contact with the fluid.

[0038] The adhesive 21f may have electrical insulation properties and heat resistance. For example, the adhesive 21f may have heat resistance of 100 degrees or more so that it can withstand the heat during the electrochemical reaction. The adhesive 21f may be, for example, an acrylic adhesive, a silicon adhesive, or an epoxy adhesive.

[0039] 6 and 7, the flow path plate outer frame 21 has an anode fluid inlet communication hole 22, an anode fluid outlet communication hole 23, a cathode fluid inlet communication hole 24, and a cathode fluid outlet communication hole 25. The anode fluid inlet communication hole 22 and the anode fluid outlet communication hole 23 are also simply referred to as anode fluid communication holes. The cathode fluid inlet communication hole 24 and the cathode fluid outlet communication hole 25 are also simply referred to as cathode fluid communication holes. These communication holes 22, 23, 24, and 25 are each provided at a distance from the flow path plate 20. These communication holes 22, 23, 24, and 25 each penetrate the flow path plate outer frame 21 in the thickness direction (stacking direction).

[0040] When the electrode plate 10 and electrode plate outer frame 11 and the flow path plate 20 and flow path plate outer frame 21 are stacked, the communication holes 22, 23, 24, and 25 overlap with the corresponding communication holes 12, 13, 14, and 15. The anode fluid inlet communication hole 12 communicates with the anode fluid inlet communication hole 22, and the anode fluid outlet communication hole 13 communicates with the anode fluid outlet communication hole 23. The cathode fluid inlet communication hole 14 communicates with the cathode fluid inlet communication hole 24, and the cathode fluid outlet communication hole 15 communicates with the cathode fluid outlet communication hole 25. The anode fluid inlet communication holes 12 and 22 communicate with the anode fluid inlet hole 7a, and the anode fluid outlet communication holes 13 and 23 communicate with the anode fluid outlet hole 7b. The cathode fluid inlet manifolds 14 and 24 communicate with the cathode fluid inlet hole 7c, and the cathode fluid outlet hole 7d communicates with the cathode fluid outlet manifolds 15 and 25.

[0041] Anode fluid supplied from the outside passes through the anode fluid inlet hole 7a and flows into the anode fluid inlet manifolds 12 and 22. After the electrochemical reaction has occurred in the anode flow path 26, the anode fluid flows from the anode fluid outlet manifolds 13 and 23 to the anode fluid outlet hole 7b and then flows to the outside. Cathode fluid supplied from the outside passes through the cathode fluid inlet hole 7c and flows into the cathode fluid inlet manifolds 14 and 24. After the electrochemical reaction has occurred in the cathode flow path 27, the cathode fluid flows from the cathode fluid outlet manifolds 15 and 25 to the cathode fluid outlet hole 7d and then flows to the outside.

[0042] The electrochemical cell 2 further includes anode connecting grooves 28a, 28b and cathode connecting grooves 29a, 29b. As shown in Figures 6 and 7, the anode connecting grooves 28a, 28b and the cathode connecting grooves 29a, 29b may be provided in the flow path plate outer frame 21. That is, the flow path plate outer frame 21 may have the anode connecting grooves 28a, 28b and the cathode connecting grooves 29a, 29b.

[0043] The anode communication groove 28a connects the anode fluid inlet manifold 22 and the anode flow path 26. That is, the anode communication groove 28a allows the anode fluid to flow from the anode fluid inlet manifold 22 to the anode flow path 26. The anode communication groove 28b connects the anode flow path 26 and the anode fluid outlet manifold 23. That is, the anode communication groove 28b allows the anode fluid to flow from the anode flow path 26 to the anode fluid outlet manifold 23.

[0044] The anode communication grooves 28a, 28b may be composed of multiple grooves formed on the surface of the flow path plate outer frame 21. The anode communication grooves 28a, 28b may be composed of through grooves formed in the sheet material 21e on the outermost surface of the flow path plate outer frame 21 (see FIG. 8). The anode communication groove 28a may be formed to extend from the anode fluid inlet manifold 22 to the anode flow path 26. The anode communication groove 28b may be formed to extend from the anode flow path 26 to the anode fluid outlet manifold 23. As shown in FIG. 7, the anode communication grooves 28a, 28b may be serpentine flow paths having multiple bends.

[0045] The cathode communication groove 29a communicates between the cathode fluid inlet manifold 24 and the cathode flow path 27. That is, the cathode communication groove 29a allows the cathode fluid to flow from the cathode fluid inlet manifold 24 to the cathode flow path 27. The cathode communication groove 29b communicates between the cathode flow path 27 and the cathode fluid outlet manifold 25. That is, the cathode communication groove 29b allows the cathode fluid to flow from the cathode flow path 27 to the cathode fluid outlet manifold 25.

[0046] The cathode communication grooves 29a, 29b may be composed of a plurality of grooves formed on the surface of the flow path plate outer frame 21. The cathode communication grooves 29a, 29b may be composed of through grooves formed in the sheet material 21a on the outermost surface of the flow path plate outer frame 21 (see FIG. 8). The cathode communication groove 29a may be formed so as to extend from the cathode fluid inlet manifold 24 to the cathode flow path 27. The cathode communication groove 29b may be formed so as to extend from the cathode flow path 27 to the cathode fluid outlet manifold 25. As shown in FIG. 6, the cathode communication grooves 29a, 29b may be parallel flow paths that extend linearly.

[0047] 6 and 7, the flow path plate outer frame 21 may have a sealant 30. As shown in FIG. 7, the sealant 30 may be provided so as to surround the anode fluid inlet manifold 22, the anode connection groove 28a, the anode flow path 26, the anode connection groove 28b, and the anode fluid outlet manifold 23. The sealant 30 may be provided so as to surround the cathode fluid inlet manifold 24. The sealant 30 may be provided so as to surround the cathode fluid outlet manifold 25. As shown in FIG. 6, the sealant 30 may be provided so as to surround the cathode fluid inlet manifold 24, the cathode connection groove 29a, the cathode flow path 27, the cathode connection groove 29b, and the cathode fluid outlet manifold 25. The sealant 30 may be provided so as to surround the anode fluid inlet manifold 22. The sealant 30 may be provided so as to surround the anode fluid outlet manifold 23.

[0048] The sealant 30 is a member that seals gaps between the electrode plate 10 and the electrode plate outer frame 11 and the flow path plate 20 and the flow path plate outer frame 21 when they are stacked together to prevent anode fluid and cathode fluid from leaking out through the gaps. The sealant 30 may be an elastic material such as rubber. In this case, when the electrode plate 10 and the electrode plate outer frame 11 and the flow path plate 20 and the flow path plate outer frame 21 are stacked and fastened together in a direction toward each other, the sealant 30 is compressed between the electrode plate outer frame 11 and the flow path plate outer frame 21, and the resulting reaction force seals the gaps between the components. The sealant 30 may also be an adhesive. In this case, when the electrode plate 10 and the electrode plate outer frame 11 and the flow path plate 20 and the flow path plate outer frame 21 are stacked together and fastened together in a direction toward each other, the electrode plate outer frame 11 and the flow path plate outer frame 21 are adhered to each other, thereby sealing the gaps between the components.

[0049] In this embodiment, the electrode plate outer frame 11 has a gap 41, and the flow path plate outer frame 21 has a gap .

[0050] The void 41 is a portion of the electrode plate outer frame 11 where the sheet materials 11a, 11b, and 11c and the adhesive material 11f are not provided. The void 41 is provided in a partial region of the electrode plate outer frame 11. The void 41 is provided in a position where it overlaps with at least one of the anode connection grooves 28a and 28b and the cathode connection grooves 29a and 29b in a plan view. The void 41 may also be provided in a position where it overlaps with both the anode connection groove 28a and the cathode connection groove 29a in a plan view. In the examples shown in FIGS. 2 and 4 to 7, the void 41 is provided in the region indicated by the symbol R.

[0051] The void 42 is a portion of the flow path plate outer frame 21 where the sheet materials 21a, 21b, 21c, 21d, and 21e and the adhesive material 21f are not provided. The void 41 is provided in a partial region of the flow path plate outer frame 21. The void 42 is provided in a position where it overlaps with at least one of the anode connection grooves 28a and 28b and the cathode connection grooves 29a and 29b in a plan view. The void 42 may be provided in a position where it overlaps with both the anode connection groove 28a and the cathode connection groove 29a in a plan view. The void 42 may be provided in a position where it overlaps with the void 41 in a plan view. In the examples shown in FIGS. 2 and 4 to 7, the void 42 is provided in the region indicated by the symbol R.

[0052] Fig. 8 is a cross-sectional view taken along the line BB in Fig. 2. That is, Fig. 8 is a cross-sectional view of the electrode plate outer frame 11 and the flow path plate outer frame 21 at positions where the gaps 41 and 42 are provided.

[0053] 8, the gap 41 may be provided between the sheet material 11a and the sheet material 11c. That is, the gap 41 may be formed in the electrode plate outer frame 11 by providing an area where the sheet material 11b and the adhesive material 11f are absent between the sheet material 11a and the sheet material 11c in the stacking direction.

[0054] As shown in FIG. 8 , a reinforcing sheet 51 is provided in the gap 41. The reinforcing sheet 51 is a member that reinforces the electrode plate outer frame 11 to prevent a decrease in the rigidity of the electrode plate outer frame 11. The reinforcing sheet 51 may be provided so as to fill the gap 41. The reinforcing sheet 51 may have a thickness that corresponds to the distance between the sheet material 11a and the sheet material 11c in the stacking direction. In other words, the reinforcing sheet 51 may have a thickness that is the sum of the thickness of the sheet material 11b, the thickness of the adhesive material 11f that bonds the sheet material 11a and the sheet material 11b, and the thickness of the adhesive material 11f that bonds the sheet material 11b and the sheet material 11c.

[0055] The reinforcing sheet 51 may contain a metal material. The reinforcing sheet 51 may be made of a highly rigid metal material such as a metal plate. The reinforcing sheet 51 may also be made of an electrically insulating material such as a resin material such as fluororesin, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), or polyethylene naphthalate (PEN), or a rubber material such as fluororubber, ethylene propylene diene rubber (EPDM), or silicone rubber. In particular, the reinforcing sheet 51 may contain the same material as the sheet materials 11a, 11b, and 11c of the electrode plate outer frame 11. The reinforcing sheet 51 may also be made of the same material as the sheet materials 11a, 11b, and 11c.

[0056] 8, the gap 42 may be provided between the sheet material 21b and the sheet material 21d. That is, the gap 42 may be formed in the flow path plate outer frame 21 by providing an area where the sheet material 21c and the adhesive material 21f are absent between the sheet material 21b and the sheet material 21d in the stacking direction.

[0057] As shown in Fig. 8, a reinforcing sheet 52 is provided in the gap 42. The reinforcing sheet 52 is a member that reinforces the flow path plate outer frame 21 to prevent a decrease in the rigidity of the flow path plate outer frame 21. The reinforcing sheet 52 may be provided so as to fill the gap 42. The reinforcing sheet 52 may have a thickness that corresponds to the distance between the sheet material 21b and the sheet material 21d in the stacking direction. In other words, the reinforcing sheet 52 may have a thickness that is the sum of the thickness of the sheet material 21c, the thickness of the adhesive material 21f that bonds the sheet material 21b and the sheet material 21c, and the thickness of the adhesive material 21f that bonds the sheet material 21c and the sheet material 21d.

[0058] The reinforcing sheet 52 may contain a metal material. The reinforcing sheet 52 may be made of a highly rigid metal material such as a metal plate. The reinforcing sheet 52 may also be made of an electrically insulating material such as a resin material such as fluororesin, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), or polyethylene naphthalate (PEN), or a rubber material such as fluororubber, ethylene propylene diene rubber (EPDM), or silicone rubber. In particular, the reinforcing sheet 52 may contain the same material as the sheet materials 21a, 21b, 21c, 21d, and 21e of the flow path plate outer frame 21. The reinforcing sheet 52 may also be made of the same material as the sheet materials 21a, 21b, 21c, 21d, and 21e.

[0059] Next, the operation of the electrochemical cell 2 and the electrochemical cell stack 1 according to this embodiment will be described.

[0060] First, cathode fluid and anode fluid are supplied to the electrochemical cell stack 1. The cathode fluid supplied to the electrochemical cell stack 1 passes through the cathode fluid inlet holes 7c and flows into the cathode fluid inlet manifolds 14, 24 of each electrochemical cell 2. Next, the cathode fluid flows from the cathode fluid inlet manifold 24 into the cathode communication groove 29a in the flow path plate outer frame 21, and flows through the cathode communication groove 29a. Next, the cathode fluid that has flowed through the cathode communication groove 29a flows into the cathode flow path 27 in the flow path plate 20. The cathode fluid then flows through the cathode flow path 27 while coming into contact with the cathode electrode 18 of the electrode plate 10.

[0061] The anode fluid supplied to the electrochemical cell stack 1 passes through the anode fluid inlet holes 7a and flows into the anode fluid inlet manifolds 12 and 22 of each electrochemical cell 2. The anode fluid then flows from the anode fluid inlet manifold 22 into the anode communication groove 28a in the flow path plate outer frame 21, and flows through the anode communication groove 28a. After flowing through the anode communication groove 28a, the anode fluid then flows into the anode flow path 26 in the flow path plate 20. The anode fluid then flows through the anode flow path 26 while coming into contact with the anode 17 on the electrode plate 10.

[0062] At least a portion of the constituent substances of the cathode fluid in contact with the cathode electrode 18 and the anode fluid in contact with the anode electrode 17 reacts with the catalyst attached to the electrodes and becomes ionized. In this state, when a predetermined voltage is applied to both ends of the electrochemical cell stack 1 in the stacking direction, a potential difference is generated between the cathode electrode 18 and the anode electrode 17 across the electrically insulating diaphragm 16 of the electrode plate 10. This causes certain ionized substances in the fluids to pass through the diaphragm 16, causing an electrochemical reaction that changes the material composition of the cathode fluid and the anode fluid.

[0063] For example, by supplying water (HO) to the anode side, a water electrolysis reaction can be achieved in which hydrogen (H) is extracted from the cathode outlet side. Alternatively, by supplying water (HO) to the anode side and carbon dioxide (CO) to the cathode side, a carbon dioxide electrolysis reaction can be achieved in which a mixed gas containing carbon monoxide (CO) is extracted from the cathode outlet side.

[0064] After the electrochemical reaction, the cathode fluid flows from the cathode flow channels 27 in the flow channel plate 20 into the cathode communication groove 29b in the flow channel plate outer frame 21. The cathode fluid then flows through the cathode communication groove 29b. After flowing through the cathode communication groove 29b, the cathode fluid reaches the cathode fluid outlet manifold 25. The cathode fluid then flows from the cathode fluid outlet manifolds 15 and 25 through the cathode fluid outlet hole 7d to the outside.

[0065] After the electrochemical reaction, the anode fluid flows from the anode flow passage 26 in the flow passage plate 20 into the anode communication groove 28b in the flow passage plate outer frame 21. The anode fluid then flows through the anode communication groove 28b. After flowing through the anode communication groove 28b, the anode fluid reaches the anode fluid outlet communication hole 23. The anode fluid then flows from the anode fluid outlet communication holes 13 and 23 to the outside through the anode fluid outlet hole 7b.

[0066] Next, the effects of the electrochemical cell 2 and the electrochemical cell stack 1 according to this embodiment will be described.

[0067] Generally, in an electrochemical cell stack, a certain pressure is applied to the electrochemical cells in the stacking direction by fastening or the like to tightly bond the electrode plates and flow path plates. Consider a typical electrochemical cell stack 101 as shown in FIG. 9 . This electrochemical cell stack 101 is configured by stacking multiple electrochemical cells 102. The electrochemical cells 102 include an electrode plate outer frame 111 joined to the outer periphery of an electrode plate (not shown) and a flow path plate outer frame 121 joined to the outer periphery of a flow path plate (not shown). The electrode plate outer frame 111 is configured by three sheet materials 111a, 111b, and 111c bonded in the stacking direction with adhesive 111f. The flow path plate outer frame 121 is configured by five sheet materials 121a, 121b, 121c, 121d, and 121e bonded in the stacking direction with adhesive 121f. The flow path plate outer frame 121 also has anode connection grooves 128a, 128b and cathode connection grooves 129a, 129b. The anode connection grooves 128a, 128b are configured as through grooves formed in the sheet material 121e on the outermost surface of the flow path plate outer frame 121, and the cathode connection grooves 129a, 129b are configured as through grooves formed in the sheet material 121a on the outermost surface of the flow path plate outer frame 121.

[0068] In electrochemical cell stack 101 configured as described above, when a certain pressure is applied in the stacking direction, adhesives 111f and 121f may be deformed by the pressure, and communication grooves 128a, 128b, 129a, and 129b may be crushed, as shown in Fig. 10. If communication grooves 128a, 128b, 129a, and 129b are crushed, the flow path area for the anode fluid and cathode fluid to flow may decrease, and the amount of electrochemical reaction may decrease.

[0069] In contrast, according to the present embodiment, the electrode plate outer frame 11 has a gap 41 where the sheet materials 11a, 11b, and 11c and adhesive 11f are not provided at a position overlapping at least one of the anode connection grooves 28a, 28b and the cathode connection grooves 29a, 29b in a plan view, and a reinforcing sheet 51 is provided in the gap 41 of the electrode plate outer frame 11. As a result, the adhesive 11f is not provided at a position overlapping the connection groove in a plan view in the electrode plate outer frame 11, and instead, the reinforcing sheet 51 is provided. This reduces the collapse of the connection groove due to deformation of the adhesive 11f when a certain pressure is applied in the stacking direction by fastening or the like. As a result, the reduction in the flow path area for the anode fluid and the cathode fluid can be reduced, suppressing a decrease in the electrochemical reaction rate.

[0070] Furthermore, according to this embodiment, the gap 41 in the electrode plate outer frame 11 is positioned so as to overlap both the anode connecting grooves 28a, 28b and the cathode connecting grooves 29a, 29b in a plan view. This reduces the collapse of both the anode connecting grooves 28a, 28b and the cathode connecting grooves 29a, 29b when a certain pressure is applied in the stacking direction by fastening or the like. This further reduces the decrease in the amount of electrochemical reaction.

[0071] Furthermore, according to this embodiment, the flow path plate outer frame 21 has a gap 42 where the sheet materials 21a, 21b, 21c, 21d, and 21e and the adhesive 21f are not provided at a position overlapping at least one of the anode connection grooves 28a and 28b and the cathode connection grooves 29a and 29b in a plan view, and a reinforcing sheet 52 is provided in the gap 42 of the flow path plate outer frame 21. As a result, the adhesive 21f is not provided at a position overlapping the connection groove in a plan view of the flow path plate outer frame 21, and instead the reinforcing sheet 52 is provided. Therefore, when a certain pressure is applied in the stacking direction by fastening or the like, crushing of the connection groove due to deformation of the adhesive 21f can be reduced. As a result, the reduction in the flow path area through which the anode fluid and the cathode fluid flow can be reduced, and a decrease in the electrochemical reaction rate can be suppressed.

[0072] Furthermore, according to this embodiment, the gap 42 of the flow path plate outer frame 21 is positioned so as to overlap both the anode connecting grooves 28a, 28b and the cathode connecting grooves 29a, 29b in a plan view. This reduces the collapse of both the anode connecting grooves 28a, 28b and the cathode connecting grooves 29a, 29b when a certain pressure is applied in the stacking direction by fastening or the like. This further reduces the decrease in the amount of electrochemical reaction.

[0073] Furthermore, according to this embodiment, the reinforcing sheet 51 contains a metal material. This increases the rigidity of the electrode plate outer frame 11 at the position that overlaps the connecting groove in a plan view. This makes it possible to suppress deformation of the adhesive 11f when a certain pressure is applied in the stacking direction, thereby reducing crushing of the connecting groove. This further suppresses a decrease in the amount of electrochemical reaction.

[0074] Furthermore, according to this embodiment, the reinforcing sheet 51 contains the same material as the sheet materials 11a, 11b, and 11c of the electrode plate outer frame 11. This eliminates the need to prepare a separate sheet of material for manufacturing the reinforcing sheet 51. This makes it possible to suppress an increase in the manufacturing cost of the electrochemical cell 2.

[0075] Furthermore, according to this embodiment, the reinforcing sheet 52 contains a metal material. This increases the rigidity of the flow path plate outer frame 21 at the position that overlaps the communication groove in a plan view. This makes it possible to suppress deformation of the adhesive 21f when a certain pressure is applied in the stacking direction, thereby reducing crushing of the communication groove. This further suppresses a decrease in the amount of electrochemical reaction.

[0076] Furthermore, according to this embodiment, the reinforcing sheet 52 contains the same material as the sheet materials 21a, 21b, 21c, 21d, and 21e of the flow path plate outer frame 21. This eliminates the need to prepare a separate sheet of material for manufacturing the reinforcing sheet 52. This makes it possible to suppress an increase in the manufacturing cost of the electrochemical cell 2.

[0077] According to the embodiment described above, it is possible to suppress a decrease in the amount of electrochemical reaction.

[0078] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims.

[0079] For example, the width, number and cross-sectional shape of the grooves of each flow path in the flow path plate, the number of bends and the chamfered shape of the bends of the serpentine flow path, and the shapes of the branching and merging parts of the parallel flow path are not limited to those shown in the drawings.Furthermore, the shapes of the connecting grooves in the outer frame of the flow path plate are not limited to those shown in the drawings.

[0080] Furthermore, the configurations of the electrode plate outer frame and the flow path plate outer frame are not limited to those shown in the drawings. For example, in the above-described embodiment, the electrode plate outer frame is made up of three sheet materials, but the electrode plate outer frame may be made up of two sheet materials, or four or more sheet materials. Also, in the above-described embodiment, the flow path plate outer frame is made up of five sheet materials, but the flow path plate outer frame may be made up of two to four sheet materials, or six or more sheet materials.

[0081] Furthermore, in the above-described embodiment, an example has been described in which the electrode plate outer frame has a gap and the flow path plate outer frame also has a gap. However, this is not limited to this, and the electrode plate outer frame may have a gap but the flow path plate outer frame may not have a gap. Similarly, the flow path plate outer frame may have a gap but the electrode plate outer frame may not have a gap. In other words, it is sufficient that at least one of the electrode plate outer frame and the flow path plate outer frame has a gap.

[0082] Furthermore, the void portion may be positioned in any way as long as it overlaps with at least one of the anode connection groove and the cathode connection groove in a plan view. For example, the void portion may be positioned so that it overlaps only with the anode connection groove in a plan view, or so that it overlaps only with the cathode connection groove in a plan view. Furthermore, for example, the void portion may be positioned so that it overlaps with almost the entirety of both the anode connection groove and the cathode connection groove in a plan view, as indicated by the symbol R in FIGS. 11 and 12 .

[0083] Furthermore, in the above-described embodiment, an example has been described in which the flow path plate outer frame has an anode connection groove and a cathode connection groove. However, this is not limited to this, and the flow path plate outer frame may have an anode connection groove, and the electrode plate outer frame may have a cathode connection groove. Alternatively, the flow path plate outer frame may have a cathode connection groove, and the electrode plate outer frame may have an anode connection groove. Alternatively, the electrode plate outer frame may have an anode connection groove and a cathode connection groove. In other words, it is sufficient that the electrochemical cell has an anode connection groove and a cathode connection groove. [Explanation of symbols]

[0084] 1: electrochemical cell stack, 2: electrochemical cell, 10: electrode plate, 11: electrode plate outer frame, 11a, 11b, 11c: sheet material, 11f: adhesive, 12: anode fluid inlet communication hole, 13: anode fluid outlet communication hole, 14: cathode fluid inlet communication hole, 15: cathode fluid outlet communication hole, 16: diaphragm, 17: anode electrode, 18: cathode electrode, 20: flow path plate, 21: flow path plate outer frame, 21a, 21b, 21c, 21d, 21e: sheet material, 21f: adhesive material, 22: anode fluid inlet communication hole, 23: anode fluid outlet communication hole, 24: cathode fluid inlet communication hole, 25: cathode fluid outlet communication hole, 26: anode flow path, 27: cathode flow path, 28a, 28b: anode connection groove, 29a, 29b: cathode connection groove, 41, 42: void portion, 51, 52: reinforcing sheet

Claims

1. 1. An electrochemical cell comprising: an electrode plate having a diaphragm, an anode electrode disposed on one main surface of the diaphragm, and a cathode electrode disposed on the other main surface of the diaphragm; a flow path plate that is stacked on the electrode plate in a stacking direction, the flow path plate being disposed opposite the anode electrode and having an anode flow path through which an anode fluid flows, and a cathode flow path that is disposed opposite the cathode electrode and through which a cathode fluid flows; an electrode plate outer frame joined to the outer periphery of the electrode plate; a flow path plate outer frame joined to an outer periphery of the flow path plate, the electrode plate outer frame and the flow path plate outer frame have anode fluid communication holes and cathode fluid communication holes that communicate in the stacking direction, the electrochemical cell further includes an anode communication groove that communicates the anode fluid communication hole with the anode flow path, and a cathode communication groove that communicates the cathode fluid communication hole with the cathode flow path, the electrode plate outer frame is configured by bonding a plurality of sheet materials with an adhesive in the stacking direction, the electrode plate outer frame has a gap portion where the sheet material and the adhesive material are not provided at a position overlapping with at least one of the anode connection groove and the cathode connection groove in a plan view, an electrochemical cell, wherein a reinforcing sheet is provided in the gap portion of the electrode plate outer frame;

2. 2 . The electrochemical cell according to claim 1 , wherein the gap portion of the electrode plate outer frame is provided at a position overlapping both the anode connecting groove and the cathode connecting groove in a plan view.

3. the flow path plate outer frame is configured by bonding a plurality of sheet materials with an adhesive in the stacking direction, the flow path plate outer frame has a gap portion where the sheet material and the adhesive material are not provided at a position overlapping with at least one of the anode connection groove and the cathode connection groove in a plan view, The electrochemical cell according to claim 1 , wherein a reinforcing sheet is provided in the gap of the flow path plate outer frame.

4. 4. The electrochemical cell according to claim 3, wherein the gap portion of the flow path plate outer frame is provided at a position overlapping with both the anode connection groove and the cathode connection groove in a plan view.

5. The electrochemical cell of claim 1 , wherein the stiffening sheet comprises a metallic material.

6. The electrochemical cell of claim 1 , wherein the reinforcing sheet comprises the same material as the sheet material of the electrode plate outer frame.

7. 1. An electrochemical cell comprising: an electrode plate having a diaphragm, an anode electrode disposed on one main surface of the diaphragm, and a cathode electrode disposed on the other main surface of the diaphragm; a flow path plate that is stacked on the electrode plate in a stacking direction, the flow path plate being disposed opposite the anode electrode and having an anode flow path through which an anode fluid flows, and a cathode flow path that is disposed opposite the cathode electrode and through which a cathode fluid flows; an electrode plate outer frame joined to the outer periphery of the electrode plate; a flow path plate outer frame joined to an outer periphery of the flow path plate, the electrode plate outer frame and the flow path plate outer frame have anode fluid communication holes and cathode fluid communication holes that communicate in the stacking direction, the electrochemical cell further includes an anode communication groove that communicates the anode fluid communication hole with the anode flow path, and a cathode communication groove that communicates the cathode fluid communication hole with the cathode flow path, the flow path plate outer frame is configured by bonding a plurality of sheet materials with an adhesive in the stacking direction, the flow path plate outer frame has a gap portion where the sheet material and the adhesive material are not provided at a position overlapping with at least one of the anode connection groove and the cathode connection groove in a plan view, an electrochemical cell, wherein a reinforcing sheet is provided in the gap portion of the flow path plate outer frame;

8. 8. The electrochemical cell according to claim 7, wherein the gap portion of the flow path plate outer frame is provided at a position overlapping with both the anode connection groove and the cathode connection groove in a plan view.

9. The electrochemical cell of claim 7 , wherein the stiffening sheet comprises a metallic material.

10. The electrochemical cell of claim 7 , wherein the reinforcing sheet comprises the same material as the sheet material of the flow path plate outer frame.

11. An electrochemical cell stack comprising a plurality of electrochemical cells according to any one of claims 1 to 10 stacked on top of one another.

Images